Underground pipe networks are used when distributing e.g. utility water, waste water, central heating, natural gas or other fluids over large areas. To enable that sections of the buried pipe network can be isolated e.g. during repair or fault localisation or simply to control the distribution in the network it is known to provide valves at strategic nodes and other locations in the pipe network.
However, these valves may be in use for several decades and even if the exact type of valve used at a specific location in the network was properly documented at installation, this information may get lost over time e.g. due to mergers, fire, replacement of defect valves or other. And since the valves typically are located on the buried pipes it is often difficult to subsequently identify the specific valve type without having to unearth it.
From European patent no. 0 788 573 it is known to read identification information from a sealed electronic package in the valve by means of a key used for engaging an operating device on the valve to change the status—i.e. open or closed—of the buried valve. But valves are buried at very different depths and keys of many different lengths will therefore have to be used in the same network.
From German patent application no. 10 2009 019 984 it is therefore known to provide a buried valve with an extension spindle at installation. The extension spindle enables that the valve can be operated from the ground surface no matter how deep it is buried. The valve is furthermore provided with RFID (Radio Frequency Identification) chips provided with antenna means enabling that valve identification information can be wirelessly read from the ground surface. However, such wireless transmission is vulnerable particularly in light of the relatively long lifespan of a typical valve. Furthermore, such wireless communication is only one-way.